Art of manufacturing shoe stiffeners



' 1,620,784 March .15, 1927. F RKCKS ART OF MANUFACTURING SHOE STIFFENERS Filed March 28, 1925 1 Patented Mar. 15, 1927.

UNITED STATESPATENT OFFICE.

FRED EIcKs, 0E LEICESTER, ENGLAND, AssrGNoE TO UNITED SHOE ntAcnIN EY co v :PoEA'rIoN, 0E PA'IERSON,

NEW Jnnsriirlt CORPORATION 01 NEW'JEESEY.

ART OF MANUFACTURING SHOE STIFFENEBS.

Application filed March- 28, 1925, Serial No.

This invention relates to the making of stiffened parts of boot and shoe uppers and is herein described in connection with the stiffening of the toe portions of the uppers of boots and shoes.

Of recent years there has come into use a type of box toe blank, the thermoplastic box toe blank first described in United States Letters Patent No. 1,070,406, granted Aug. 19, 1913, upon'an application filed :in the name of'Fra'nk E. Butterfield, which, owing to its many advantages, has largely displaced the types formerly in use. The very property, however, of this type of box toe blank which renders it so advantageous, namely its ability to soften merely by heating and to set immediately it cools, is one that brings with it in certain circumstances some likelihood of trouble for the shoe manufacturer. For example, if a shoe made with such abox toe blank be exposed in a shop Window to an unusual degree of summer-heat too soon after its manufacture and before the elasticity of the upper, stretched over the box toe blank, has disappeared, the box toe blank may soften to a'degree admitting of the upper contracting andwrinkling the toe end of the upper of the shoe. Again the box toe blank may become undesirably weak at the temperature to which it may be exposed in wear in tropical climates. \Vhen these conditions present themselves, it is usually where, in the desire to produce a box toe blank that is rendered workable by a low degree of heat and a short period of heating and that cools to a set condition at a comparatively slow rate, the shoe manufacturer makes use of a thermoplastic medium in the blank which softens easily and where, therefore, he takes some risk in reducing the margin of safety.

In order to avoid the occurrence of such disadvantageous results as those referred to; above, the present invention in one aspect relates to a method of making stiffened parts of boots and shoes which comprises placing in the upper in superposed relation a layer of thermoplastic stiffening substance and a layer of heat-resistant substance capable of being softened by a solvent which will not mounted upon a 19,160, and in Great Britain April 11, 192-1.

affect the thermoplastic substance, lasting the upper while the substances are soft, and

allowing the substances to harden. Conveniently the thermoplastic substance may be waterproof and the heat-resistant'substance water-soluble, since such substances are readily available and cooperate effectively to produce the desired result. Asan example of one Way inwhich the method may be'practised, there may be placed in the upper at a convenlent stage in its manufacture a compo'site blank made up of a layerof fabric impregnated with a waterproof thermoplastic substance and a superposed layer of fabr1c lmpregnated with the water-soluble substance, the composite blank being softened before the lasting operation, if softening is required, by subjecting it to the action of steam. By employing a method of this kind, the manufacturing advantages of the thermoplastic type of stiffener-such for example as the permissibility of Withdrawing the last quickly-are preserved; and at the same time, adequate rigidity of the box toe. under exposure of the finished shoe to abnormal conditions of temperature is secured.

,In other aspects, the invention relates to a stiffener comprising a layer of fabric'impregnated with a waterproof, thermoplastic stiffening substance and a superposed layer of fabric impregnated with a heat-resistant, water-soluble stiffening substance and to a shoe having such a stiffener incorporated therein.

Referring now to the accompanying drawings,

Figure 1 is a longitudinal section of a shoe upper complete except for the stiffening of the toe portion, the upper being shown last to the shape'of which it is to be conformed.

.Figure 2 is a perspective/ofv a box ltoe,

blank.

usual manneran assembled upper of a shoe heat-resistant,

comprising the upper proper of leather, and

a fabric lining. The leather upper comprises among other parts the vamp 3 and the.

toe cap which overlaps the forward edge of the vamp and is fastened to the vamp'by stitches 7. The lining comprises the lining proper 11 and a so-called plug 9 having a contour similar to. that of the toe cap and stitched at 10 to the lining.

As "has 'been indicated above, the method of the present invention which, when employed for stiffening the toe portion of a shoe, comprises placing in the toe portion of the upper two superposed layers of stiffenistics, may be -the use of softens both layers.

toe cap, and the upper lasted remain on the last until the blank .has become ing substances having the stated characterpractised in various Ways. For example, there is shown in Figure 2 a box toe blank which may conveniently be employed. This blank is a composite one and consists of a layer of felt or other fabric 13 impregnated with a waterproof thermoplastic substance such as a mixture of rosin and Monfan wax, and a superposed adhering layer of fabric such as canvas 15 impregnated with a water-soluble adhesive such as dextrin. "In practising the invention'with such a box-toe blank, the blank is first subjected to the action of steam which The soft blank is then placed in the upper between the plug and the and allowed to sufiiciently-hard to permit the'last to be withdrawn. In this connection it should be noted that, owing to the presence of the therblank moplastic layer which sets immediately upon cooling, the last may be withdrawn promptly. Instead of softening the composite blank and placing the blank in the upper just prior to the lasting operation, the

lank may obviously be place or fastened in the upperat any desirable stage in the manufacture of the shoe and then softened while it is in place just before the upper is lasted. 7

It should also be noted that the composite blank instead of being made up of two layers of. impregnated fabric, may consist of a layer of impregnated fabric like 13 coated with a water-soluble adhesive, ormof a layer of thermoplastic stiflening substance having a backing of impregnated canvas, or of a layer of thermoplastic stiffening substance coated with awater-soluble adhesive, the only essential feature being that there shall be placed in the toe portion of the upper of the shoe two layers of stiffening substances both in softened condition, one of which is thermoplastic and the other of which is heat resistant, as has been described.

Instead of using the composite box toe separate blanks may be used, one being practically like the layer- 13 of the composite blank, namely a piece of fabric impregnated with a thermoplastic stiffening substance, and the other being practically like the 'layer 15, a piece of canvas impregnated with a water-soluble stiflening' substance. ,In case which has been described above, two

the name of Brock.

to the shape of thelast and one two box toe blanks are used, they may con- Again, the method may be practised by thoroughly soakinga layer of the lining material, such as the plug 9, with a suitable solution of dextrin, placing-be tween the lining proper and the plug a hot thermoplastic box toe blank of the well-known type and then lasting the upper so that, when the toe portion of the lasted shoe is cold and. dry, the

lining proper will .bes t uck to the thermoplastic stifi'ener by the. adhesive action of the impregnant substance, and the plug will be stuck to the toe cap on one face and to the thermoplastic stiffener on the other by the adhesive action of the dextrin. This particular manner of practising the method is particularly advantageous for the following reason. When a thermoplastic stiffener blank is used, it is usually placed next to the toe cap; It. is not ordinary practicable, however, to introduce the rear edge of such a stiffener between the overlapped portions of the toe cap and the vamp so as to butt against the connecting stitches; and conse uently there is in the finished shoe no bonding between these overlapped parts. As a result,-said parts sometimes creep relatively to each other when the shoe is worn and develop an unsightly wrinkle or bulge adjacent to the stitch line. This undesirable occurrence is prevented when aheat-resistant stiffening substance is applied in the manner last described, since more or less of the substance works into the space between the overlapped f portions of the toe cap and the vamp and subsequently binds them firmly together. This binding together of the overlapped parts of a toe cap and a vamp may be obtained in the case where two separate "blanks are employed, as has been above indicated, by placing theblank COIltELiIliIlg water-soluble stiffening substance next to the toe cap with its rear edge projecting-between the overlapped portions of toe cap and vamp, this blank then acting to cement the overlapped portions together. In such instance the thermoplastic blank may be placed against the plug on either side of it as may be preferred. The lasting operation which has been referred to above may be carried out in any suitable manner, for example by the use of a machine of the type shown in United States Letters Patent N o. 1,018,47 7 granted Dec. 27, 1912, upon an application filed in Where the shoe toe is to be stiffened by two layers of material both of. which have to be softened for the conforming of the upper not be softened by heat alone or bysuch' deof which cangree of heat as it is safe to expose the work to there is no difficulty in securing the softening at or prior to the commencement of the operation, but, should the conforming be so conducted that in the partially conformed upper the layers have to be resoftened to allow of the continuance of the conforming operation, some inconvenience may then be presented in exposing. to the appropriate softening influence that layer which is resistant to heat.

One way in which this may be avoided is by terminating the heat resistant layer at the level, approximately, of the last bottom so that this blank by reason of its domed formation and its confinement between adjacent materials constitutes an effective stiffening agency without having any portion of it requiring to be lasted around the margin of the insole and on to the shoe bottom along with the margins of the other materials. In such a case therefore if the conforming be performed by pulling-over followed by lasting proper and the shoe lies some time between the operations there is no margin of the heat resistant layer requiring resoftening to that rather considerable degree which is requisite for securing the desired easy snug disposition of the materials in the vicinity of the junction of the side and bottom portions of the shoe. Usually the unwonted delay between the operations would not be such that any part of the heat resistant layer extendin g no further towards the margin of the up per materials than last indicated would have become too stiff for the easy completion of such conformation as the pulling-over opera' tion had left undone in respect of this layer and the portion the more liable to fail to satisfy this condition (i. e. the margin nearest the shoe bottom and the portion therefore most exposed to drying influences in a merely pulled-over shoe) would stillin a pulled-over shoe be in a considerable measure accessible to the moistening influence of the steam in the types of shoe-toe heaters in general use to resoften, between pulling-over and lasting, the toes of shoes containing thermo-plastic stiffeners.-

An advantage arising from restricting in such a manner the area of a heat-resistant layer of stiffening material is the reduced likelihood of pincers or other slioe engag- 7 ing parts-of shoe-upper conforming machinery becoming dirty and clogged with such material.

It is believed to be unnecessary to point out other ways in which the method of the invention may be carried out, since they are all simple variations of those which have been described.

In the description of the invention, the term lasting has been used in its broad sense as meaning the operation by which the upper is conformed to the last, whether said operation comprises one step or more than one.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. The method of making stiffened parts of boots and shoes which comprises placing in the upper in superposed relation a layer of thermoplastic stiffening substance and a layer of heat-resistant stiffening substance capable of being softened by a solvent which will not aflect the thermoplastic substance, subjecting the layer of thermoplastic substance to the action of heat and the layer of heat-resistant substance to the action of said solvent, conforming the upper to a last while the substances are soft, and allowing the substances to harden. I 2. The method of making stiflened parts of boots and shoes which comprises placing I in the upper in superposed relation 2. layer of waterproof thermoplastic stiflening substance and a layer of heat-resistant stiffening substance capable of being softened by water, softening the two substances, lasting the upper while the substances are soft, and allowing the substances to harden.

3. The method of making a shoe which includes placing in the upper in superposed relation two stiffeners one impregnated with a thermoplastic substance and the other with a heat-resistant substance capable of being softened by a solvent which will not affect the thermoplastic substance, softening the two substances, conforming'the upper to the last while the stiffeners are soft, and allowing the substances to harden.

4. The method of making a shoe which in- "cludes placing in the upper in superposed retwo substances to the action of steam to soften them, lastin the upper while the stififeners are soft, an allowing the substances to harden.

5. A shoe upper prepared for lasting having in one portion thereof in superposed relation a soft layer of a waterproof thermoplastic material and a soft layer of a watersoluble material.

6. A shoe upper prepared for lasting having in one portion thereof in superposed relation a soft layer of thermoplastic material and a soft layer of heat-resistant material containing a solvent which does not affect the thermoplastic material. 7 A shoe having incorporated in the upper thereof a two-ply stiffener comprising a layer of fabric impregnated with a thermoplastic material and a layer of fabric impregnated with a heat-resistant material.

8. A shoe stiffener comprising a layer of fabric impregnated with a waterproof thermoplastic stifi'ening substance and a superlayer of thermoplastic material and a layer posed layer of fabric impregnated "With-a of water soluble material of which one of heatresistant Water-soluble stiffening 'subsaid layers projects between the overlapped 10 stance; portions of said vamp andtoe cap. 5 91' A shoe upper comprising a vamp and a In testimony whereof I have signed my toe cap fastened together in overlapped relaname to this specification.

tion and having incorporated in said upper a l FRED RICKS. 

